Oh, you want to create the final video from within darktable. Well, I guess that's not really the scope of darktable. I would use ffmpeg to assemble the exported frames into a video. From “Post processing” onwards might be interesting here: http://houz.org/2012/07/18/dof-animation-test/

I'm not sure what "the prolonged offset and scaling" means. Maybe you could join us in IRC (irc://freenode.net/#darktable or http://webchat.freenode.net/ for webchat, channel is #darktable). I guess that would be faster than going back and forth in here.

Ok sorry,it could be added as a add-on (java JAR) to a future-release without modifying darktable core.

Next step should be to add a GUI.This could be done also in java in the same project or to have an other panel in darktable (such as ligthtable and darkroom) to handle timelapse parameters, calling the JAR after.

But I don't understand how to develop darktable... and I'm not enough "developper" to do this alone.I didn't know how to program in java at the beginning also, but I have a friend for support who was very helpful !

deflickering option (when luminosity is "blinking" during the timelapse)

This is WIP by me for some time now.By now it is partially implemented and merged to master in PR 433Complete implementation, suitable to be used for timelapses is already implemented in my branch, and awaits review.It hopefully will be available in 1.6 release.

you still have some dt.print for debug. no big deal, but you can get rid of them. you can pass nil to register_storage and get rid of show_status

os.execute will block lua until the command finishes execution. This is usually a bad idea. you should usually replace these calls with coroutine.yield("run_command",<command>) this should do the same thing but with a lua yield in the middle that allows other lua threads to run.

that last point is particularly important when you run the video at the end.

Apart from that, this all looks good. I don't think you can do your current TODO items simply with lua but I am slowly adding the complicated features. in particular

i'm mid-way in letting lua manipulate iop parameters. with that in place lua scripts would be able to interpolate between two images

I have started looking at adding UI elements with lua. Your exporter would be able to have its own UI elements in the main window instead of having them in prefs, but again it will take some time.

Without the show_status there is no pop-up to show the progress, just the progress bar in the lower left corner. (That I haven't seen till today. ;)) Perhaps I'm doing something wrong. I've attached a version without the show_status, please review it.

I don't think you can do your current TODO items simply with lua but I am slowly adding the complicated features. in particular

i'm mid-way in letting lua manipulate iop parameters. with that in place lua scripts would be able to interpolate between two images

I have started looking at adding UI elements with lua. Your exporter would be able to have its own UI elements in the main window instead of having them in prefs, but again it will take some time.

These improvements will be very appreciated.

A main task within time-lapse processing is to smooth out jumps that are the result of manual exposure adjustments during shooting. This happens mainly at shootings of sunrise or sunset. You have to adjust the exposure value between two keyframe-images.

My first thought was, to adjust the keyframes, get the image numbers and write a bash-script to manipulate the exposure-values in the xmp-files of all images between two keyframe-images. Then reimport the xmp-files in darktable. This is somewhat cumbersome and error-prone.

A much better way is to use lua within darktable. For this, the named improvements are necessary.

Advantageously lua should be able to manipulate linear modules, such as exposure, white balance, crop and rotate, contrast brightness saturation, local contrast, vibrance. (These proposed controllers I found in puplications of G.Wegner)

At the moment it doesn't work on Ubuntu, because Ubuntu removed mencode from it's repro.------

I asked on IRC, if we will have this two thing in the next darktable version:1. deflickering2. using lua to manipulate iop parameters

<LebedevRI> i really hope i will release 1. this time, in next release :)<boucman_work> tobias_, no, that one is complicated, I have protoyped something using houz's introspection that allowed me to dump all iop in text format, but integrating into DT proper is tricky...

<boucman_work> you can add UI elements with lua, though... that part is done------

So we will hopefully get some improvements with the next darktable version.------